Bearing assemblies are often used in applications where a rotating shaft is subjected to radial and axial loads. For example, the gearbox and rotating flight shaft of radar-equipped aircraft such as the rotodome of early warning command and control aircraft are subjected to substantial radial loads on the rotodome flight shaft due to air loads acting on the rotodome during flight. In addition, the flight shaft is subjected to substantial axial loads due to the weight of the rotodome and the aerodynamic forces applied during flight on the disk-shaped rotodome. In conventional rotodome gearbox and flight shaft designs, a highly complex bearing system is used, including upper and lower bearing assemblies offset along the length of the shaft from a lower “X” bearing assembly in the rotodome gearbox that is required in order to react the substantial axial loads on the shaft. This arrangement has several drawbacks including substantial wear of the upper and lower pylon bearing assemblies when the flight shaft bends, which causes unwanted walking, rotation at the inner and outer diameters of the bearings that, in turn, causes scoring of the structural support assembly. Other disadvantages of the conventional design include uneven loading of the “X” bearing that results in brinelling of the bearing races and reduced life. The current arrangement also requires time consuming maintenance procedures due to the fact that the flight shaft and gearbox are secured with common fasteners requiring removal of the flight shaft load from the gearbox as a prerequisite for removal and replacement of the gearbox.
The present invention has been developed in view of the foregoing, and to address other deficiencies of prior bearing assembly designs.